A typical vehicle seat sliding apparatus includes an upper rail and a lower rail. The upper rail supports a seat at an upper side, and the lower rail supports the upper rail so as to be relatively movable in the longitudinal direction of the upper rail. Patent document 1 describes an example of a seat sliding apparatus of which the upper rail includes two side walls opposed to each other in the widthwise direction of the upper rail and an upper wall that connects the two side walls. The upper wall includes a plurality of bolts functioning as seat fasteners (refer to FIG. 3 of patent document 1).
A seat sliding apparatus such as that described above usually includes a lock mechanism that allows for switching between a state in which movement of the upper rail relative to the lower rail is restricted and a state in which movement of the upper rail relative to the lower rail is permitted. This allows the slide position of the seat to be adjusted and the seat to be held in place at the adjusted slide position.